According to the 2010 United States Census, the percentage of immigrants in the US in 2010 was about the same as it was in 1910 — around 13%. Though the number of immigrants in the US as compared to its total population decreased significantly in the mid-20th century to about 5.4%, immigration tripled between then and the early 2000s, with about 40 million foreign-born people living in the US as of the early 2000s.
More about immigration:
The country of origin of US immigrants has changed drastically over the past century: while almost 90% of immigrants were European in the early 1900s, only around 12% were in 2010. The biggest sources of immigrants in the 21st century so far have been Mexico, India, the Philippines, and China.
An estimated 500,000 undocumented immigrants enter the US annually. Despite this, the majority of people who immigrate to the US do so legally.
The US is actually pretty low in terms of the percentage of its population that is foreign-born: about 25% of Australia’s population is composed of immigrants, as is about 17% of Canada’s.